The present invention relates to compositions to be applied on textiles to make them hydro- and oil-repellent in combination with a very good softness and with the maintenance of the textile appearance.
In order to make hydro- and oil-repellent the surfaces of various materials, the use of various types of polymers, also fluorinated, is known in the prior art. For example fluorinated polymers with various kinds of functionality can be mentioned. Specifically for textiles, fluorinated polymers having an acrylic base wherein the fluorinated part is formed of fluorocarbon chains, can be mentioned. Other fluorinated polymers used to give hydro- and oil-repellence are those having a (per)fluoropolyether structure, in particular polyurethanes. These polymers are used in the form of their aqueous dispersions -to treat textiles. Hydro- and oil-repellence depend on the kind of polymer and the functionality.
In all the patents of the prior art no reference is made to the softness of the treated textiles. This is an essential feature since the treated textiles in addition to very good hydro- and oil-repellence values must show a softness which is substantially similar to that of the untreated textiles. By textile appearance it is meant that the treatment does not substantially change the colour and the gloss with respect to the textiles as such.
U.S. Pat. No. 2,995,542, U.S. Pat. No. 3,356,628 and U.S. Pat. No. 4,529,658 relate to the synthesis of fluoroacrylic polymers and their use for the fiber and textile treatment. After treatment with these polymers, very good hydro- and oil-repellence values, higher than those obtainable with other fluorinated polymers which have other kinds of functionality and structure, are obtained. However, the fluoroacryl polymers show the following drawbacks: the fiber or textile surface appearance is modified, perspirability is reduced and textiles become stiffer. This last aspect of the treated textiles is determined by the softness examination, as called in the technical language. In case of the application of said films, the textile softness becomes worse.
The need was therefore felt to have available compositions for the surface textile treatment combining the very good hydro- and oil-repellence characteristics with the appearance and softness of the untreated textiles. In other words there was the need to find compositions which, besides conferring very good hydro- oil-repellence, did not worsen the textile softness and appearance.
It has now been surprisingly and unexpectedly found that it is possible to solve said technical problem by treating textiles with compositions in the form of aqueous dispersions as hereinunder defined.
It is an object of the present invention compositions formed of aqueous dispersions comprising a mixture of the following fluorinated polymers:
A) (meth)acrylic (co)polymers containing fluorine, and
B) cationic ionomers of fluorinated polyurethanes based on (per)fluoropolyethers,
xe2x80x83the weight ratio A):B), on the dry product, being in the range 70:30 and 30:70, preferably 60:40 and 40:60, with the proviso that component A) must not be lower than about 0.5% by weight as dry product in the dispersion.
Preferably component B) is present in the dispersion at a concentration of about 0.4% by weight, more preferably 0.5%.
The invention compositions are used in aqueous dispersions at a concentration in the range 0.7-3% w/w, preferably 0.8-1.5% w/w, still more preferably 0.9-1.3% w/w, determined as dry residue.
Component B), cationic ionomer fluorinated polyurethanes, usable in the present invention, are based on (per)-fluoropolyethers and are obtainable with known methods of the prior art. See for example EP 273,449, EP 337,312, EP 533,159, EP 689,908.
The (per) fluoropolyether-based ionomer polyurethanes have a fluorine content preferably higher than 15% by weight, more preferably higher than 25% by weight, still more preferably higher than 35% by weight, and contain in their structure hydrophilic ionic groups of cationic nature, wherein the cationic groups can be present as side groups and/or in the chain, the side groups being separated from the polymer chain by a bivalent alkylen radical ((R)a)zI, wherein zI is an integer equal to one or zero, a is an intger from 1 to 20, preferably from 3 to 10, R being of the CR1R2, Y(CR1R2)b type wherein:
Y is a linking bivalent radical, different from CR1R2, preferably xe2x80x94COOxe2x80x94, xe2x80x94CONHxe2x80x94, xe2x80x94OCONHxe2x80x94, xe2x80x94Oxe2x80x94; b is an integer from 0 to 20; R1 and R2, equal to or different from each other, are: H, aliphatic radicals having from 1 to 10 carbon atoms, cycloaliphatic radicals having from 5 to 20 carbon atoms, aromatic having from 6 to 20 carbon atoms, the cyclic radicals can optionally contain heteroatoms.
The ionomer polyurethanes are obtained by polymerization in two steps according to known various processes which have in common the following steps:
a first step, wherein a fluorinated diisocyanate prepolymer is prepared by reacting with hydrogenated diisocyanates in organic solvents of polar type, for example ketones and acetates, bifunctional (per) fluoropolyethers having alcoholic or acid functionality, optionally mixed with hydrogenated macrodiols. a second step, which depending on the processes consists of:
I) partial chain extension by chain extenders such as dials or diamines (C2-C12) and ionomers, described in the above mentioned prior art which is herein incorporated by reference, then subsequent dispersion in water and salification with polymerization completion by formation of ureic bonds; or
II) insertion of ionomers and then salification, dispersion and polymerization by chain extension in water in the presence of diamines; or
III) insertion of ionomers and completion of the chain extension in solvent to obtain the polymer having the desired molecular weight, and contemporaneous dispersion and salification in water of the so obtained polymer; alternatively the polymer can be first salified and then dispersed in water.
The hydrogenated macrodiols are for example saturated or unsaturated C2-C4 polyoxyalkylenes, for example PTMEG (polytetramethylenglycol), PEG (polyethylenglycol), PPG (polypropylenglycol), PBDH (polybutadienglycol), polyesters obtained by polycondensation of aliphatic anhydrides of dicarboxylic acids having from 4 to 9 carbon atoms with aliphatic C2-C8 diols, alone or in admixture, ex. PCL (polycaprolactonediol).
The fluorinated polyurethanes according to the present invention contain in the chain units derived from ionomers such as for example the following:
a. diols containing a substituted aminic group, having formula: 
xe2x80x83wherein RN is a linear or branched C1-C6 alkyl, zII is 1 or 2, when zII=1 the nitrogen free valence is saturated with one H atom, RCI is H or C1-C4 alkyl, NI ranges from 1 to 4;
b. tertiary alkyldialkanolamines of formula 
xe2x80x83wherein RN and NI have the above mentiond meanings; examples of said amines are methyldiethanolamine, butyldiethanolamine, methyldiisopropanolamine, or
c. the ionomers corresponding for example to the formula: 
xe2x80x83wherein T is an alkylene radical with a number of carbon atoms from 1 to 20 and has the meaning of R1, X=N(R1)2, R has the above mentioned meaning of R1; or
d. diol compounds containing substituted aminic groups corresponding to the following formulae: 
xe2x80x83wherein R has the above mentioned meaning of R1
xe2x80x83wherein R has the above mentioned meaning of R1
e is aninteger from 1 to 10.
The PFPEs contained in ionomer fluorinated polyurethanes are used in the synthesis of these polymers in the first step of the above described synthesis method; said PFPEs have average number molecular weight in the range 500-4.000, preferably 1.000-2.000, and contain repeating units selected from the following:
(CF(CF3)xe2x80x94CF2O), (CF2CF2O), (CF2(CF3)O), (CF2xe2x80x94CF(CF3)O) (CF2CF2CF2O), (CF2CF2CH2O), said units being statistically distributed in the polymer chain.
In particular they belong to one or more of the following classes:
1)xe2x80x94O(CF(CF3)xe2x80x94CF2O)n(CF(CF3)O)m(CF2O)pxe2x80x94
xe2x80x83having a random distribution of the perf luorooxyalkylene units and n, m, p are integers and have average values such as to meet the above previously mentioned requirements of average molecular weight;
2)xe2x80x94O(CF2CF2O)nxe2x80x2(CF2O)mxe2x80x2xe2x80x94
xe2x80x83with random distribution of the perfluorooxyalkylene units, mxe2x80x2 and nxe2x80x2 are integers such as to meet the above mentioned requirements of molecular weight;
3)xe2x80x94O(CF2CF2O)nxe2x80x3(CF2O)mxe2x80x3(CF(CF3)O)pxe2x80x3(CF(CF3)xe2x80x94CF2O)oxe2x80x3xe2x80x94
xe2x80x83wherein mxe2x80x3, nxe2x80x3, pxe2x80x3, oxe2x80x3 are integers such as to meet the above mentioned requirements of molecular weight;
4)xe2x80x94O(CF2xe2x80x94CF(CF3)O)txe2x80x94
xe2x80x83wherein t is an integer such as to meet the mentioned requirements of molecular weight;
xe2x80x94O(CF2CF2CF2O)sxe2x80x94 or xe2x80x94O(CF2CF2CH2O)sxe2x80x94
xe2x80x83wherein s is an integer such as to meet the above mentioned requirements of molecular weight.
Preferably the repeating units in the PFPES of the ionomer polyurethanes have the structure 1).
The ionomer fluorinated polyurethanes have a fluorine content preferably in the range 30-40% by weight.
The polymer salification is carried out with organic or inorganic acids such as hydrochloric, phosphoric, formic, acetic, lactic acid, etc. or by carrying out the nitrogen quaternization with alkylating agents known in the art, for example methyl iodide, dimethylsulphate, benzyl bromide, etc.
Said salts are prepared by adding the acid to the reaction solution containing the polyurethane in a mixed aqueous/organic solvent, wherein the organic solvent is partially or totally soluble with water, for example ethyl acetate.
The so prepared aqueous dispersions of the polyurethanes are generally stable to sedimentation during the time, also in the absence of surfactants and/or protective colloids. Optionally, if necessary, non ionic surfactants, such as ethoxylated derivatives of alcohols having a linear C12-C20 chain or alkylphenols, in amounts in the range 0.01-1.5% by weight with respect to the polymer, can be added to the dispersion; also cosolvents, more specifically polar solvents such as propylene glycol, N-methylpyrrolidone in amounts not higher than 10% by weight with respect to the polymer, can be added.
The preferred component A) fluorinated (meth)acrylic (co)polymers are formed of monomers comprising perfluoroalkyl groups preferably with C3-C30 chain, or (per)fluoropolyether groups preferably having a chain from 4 to 30 carbon atoms; optionally one or more sulphonamide groups; hydrogenated (meth)acrylic monomers known in the art, and cationic (meth)acrylic ionomer monomers.
As examples of these monomers reference is preferably made to the formulae (I), (II), (III) and (IV) reported below, wherein the substituents have the mentioned meanings.
These fluoro(meth)acrylate copolymers are for example described in the U.S. Pat. Nos. 2,803,615, 2,839,513, 2,995,542, 3,814,741, 3,356,628, 3,536,749, 4,525,423, 4,529,658, EP 622,653 and EP 870,778 as precursor acrylic monomers.
Said copolymers can be prepared for example by emulsion polymerization, in the presence of an emulsifier, catalyst and chain transfer agent as described for example in U.S. Pat. No. 4,525,423, herein incorporated by reference. For example the fluoroacrylated copolymers can be obtained by using the following monomers:
a) from 1 to 30% by weight of monomers or mixtures thereof having formula
R1O(R2O)nII[C(O)CH2O]mIICOCHxe2x95x90CH2xe2x80x83xe2x80x83(II)
xe2x80x83wherein
R1 is a C1-C20 alkyl, cycloalkyl, haloalkyl, halocycloalkyl group (halo=Cl, Br);
R2 is a C1-C6 alkylene or haloalkylene group, each R2 group can be equal to or different from the other R2 groups, at least one R1 or R2 group contains an halogen atom,
nII is an integer from zero to 10, with the proviso that when n is zero R1 is a C1-C16 haloalkyl or halocycloalkyl group;
mII is zero or 1;
b) from 60 to 80% of monomers or mixtures thereof having formula
(RfI)pIQOCOCH=CH2xe2x80x83xe2x80x83(I)
xe2x80x83wherein
RfI is a fluoroalkyl radical with C3-C30, preferably C3-C20, carbon atoms or it is a PFPE (per) fluoropolyether radical containing the above mentioned units and having a number of carbon atoms from C5 to C30;
pI is 1 or 2;
Q is a linking bridge, divalent or trivalent, e.g., aliphatic from 1 to 12 carbon atoms, or a C6-C12 aromatic group; Q can optionally contain heteroatoms such as N, O, S or carbonylimino, sulphonylimino or carbonyl groups; Q can be unsubstituted or is linked to substituents selected from the following: halogen atoms, hydroxyl groups, C1-C6 alkyl radicals; Q preferably does not contain double or triple bonds; preferably Q is selected from the following radicals: xe2x80x94CH2xe2x80x94, xe2x80x94C2H4xe2x80x94, xe2x80x94SO2N(R5)C2H4xe2x80x94, xe2x80x94SO2N(R5)CH2CH(CH3)xe2x80x94, C2H4SO2N(R5)C4H8xe2x80x94, R5 is H or a C1-C4 alkyl;
c) from 0 to 15%, preferably from 1 to 15% of monomers or mixtures thereof having formula 
xe2x80x83wherein R3 is H or methyl;
d) from 1 to 6% of cationic monomers, or mixtures thereof, of formula
CH2=C(R4)ZIVYIV+Xxe2x88x92xe2x80x83xe2x80x83(IV)
xe2x80x83wherein R4 is H or methyl,
the ZIV group is a divalent electron attracting group and has a carbonyl or aromatic group or an oxygen or sulphur atom directly linked to the monomer vinylidene radical; the ZIV group can be preferably selected from the following:
xe2x80x94COOCH2CH(OH)CH2xe2x80x94, xe2x80x94COO(CH2)kIVxe2x80x94, xe2x80x94CONH(CH2)kIV, wherein kIV is an integer from 2 to 6;
YIV+ is a monovalent organic cation and comprises (a) the pyridinium ion, (b) the N+(R6)3 ion wherein each R6 is independently H or a C1-C4 alkyl group, or two of any R6 combine to form a C4-C5 alkylene group, or two of any R6 are xe2x80x94(CH2)2xe2x80x94 and combine with an oxygen atom to give the structure xe2x80x94(CH2)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94, (c) phosphonium ions and (d) sulphonium ions; preferably YIV+ is N+(R6)3 wherein R6 is as above defined;
Xxe2x88x92 is an anion, preferably an halide (Cl, Br, I) or an alkyl sulphate;
e) from 0 to 20% of monomers containing at least a double bond, such as for example maleic anhydride, acrylonitrile, vinyl acetate, vinylchloride, vinyl fluoride, vinylidene fluoride, vinylidene cyanide, vinyl chloroacetate, vinyl silicon, ethylene, styrene, alkyl styrenes, halogenated styrenes, methacrylonitrile, N-vinyl carbazole, vinyl pyridine, vinyl alkyl ethers, vinyl alkyl keteones isoprene, butadiene, chloroprene, fluoroprene, and mixtures thereof. The preferred monomers of group a) are the esters (halo)alkyl and (halo)cycloalkyl of the (meth)acrylic acid, halo=Cl, Br, from 1 to 20 carbon atoms.
The preferred monomers of group b) are those containing C4-C12 perfluoroalkyl chains, still more preferably containing the sulphonamide group, such as for example C8F17SO2N(CH3)CH2CH2OCOCH=CH2; when RfI is based on PFPE, Txe2x80x2O(C3F6O)m(CF2O)nCF2CH2OCH2CH2OCOC(CH3)=CH2, wherein Txe2x80x2=perfluoroalkyl C1-C3, can be mentioned, optionally one or more atoms of F of Txe2x80x2, generally one F atom, are substituted by H and/or Cl; m and n are as above defined.
The monomers usable in the group b) can also have the structures corresponding to the general formula:
Txe2x80x2Oxe2x80x94(CF2CF2O)nxe2x80x2(CF2O)mxe2x80x2xe2x80x94CF2xe2x80x94Aqxe2x80x94T0
wherein Txe2x80x2, nxe2x80x2 and mxe2x80x2 have the above mentioned meanings, q is an integer from 0 to 1, A is a bivalent radical, preferably of linear aliphatic type (CH2)mxe2x80x2o wherein mxe2x80x20 is an integer from 1 to 20, or (alkylen)cycloaliphatic, (alkylen)aromatic type. A optionally can contain heteroatoms in the ring or in the alkylene chain, or it can be both a linear and branched polyalkylenoxy chain, in particular containing repeating units of the CH2CH2O, CH2CH(CH3)O, (CH2)3O, (CH2)4O type. A can also contain groups of amidic, ester, ether, COO type, of sulphide, iminic type; the carbon atom number of the cycloaliphatic compounds being from 3 to 20, for the aromatic ones from 6 to 20; the group, A can also be a combination of the mentioned types; the bond group of A with the perfluoromethylene group of the fluorinated chain can be for example: xe2x80x94Cxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94CONRxe2x80x94(R is H, alkyl, cycloaliphatic or aromatic groups having less than 15 carbon atoms), xe2x80x94CO2xe2x80x94, xe2x80x94COSxe2x80x94, xe2x80x94COxe2x80x94, one heteroatom, or the triazinic or heterocyclic aromatic groups having 5 or 6 atoms containing 2 or more heteroatoms equal to or different from each other; T0 is xe2x80x94COOCHxe2x95x90CH2, xe2x80x94COOCH2CHxe2x95x90CH2.
The aqueous dispersions according to the present invention are prepared by adding to the aqueous dispersions of the fluorinated polyurethanes, optionally containing the indicated additives, the aqueous dispersions of the fluoroacrylates, in the required weight ratios.
The fluoroacrylate aqueous dispersions, for example Scotchgard(copyright) by 3M(copyright), are available on the market.
As said, the aqueous dispersions of the present invention are used for the treatment of textiles, specifically natural fiber textiles, for example cotton, silk, wool; synthetic fibers, e.g., acrylic, polyamide, polyester fibers, etc.
The aqueous dispersions of the present invention are used as such or diluted, depending on the type of application technique on textiles. The application technique are the known ones, for example by spreading, by immersion and subsequent mechanical removal of the polymer excess deposited on the textiles, by spray or roll application.
For example when the application is made by spreading, the dispersion can be formulated by adding additives such as thickening agents, optionally together with the other conventional excipients of these formulations. In the immersion or spray application the dispersion is diluted with deionized water depending on the desired use. Tests carried out by the Applicant (see the Examples) have shown that the aqueous dispersions containing the sole component A) fluoroacrylic copolymers confer to textiles good hydro- and oil-repellent properties when said dispersions have concentrations equal to or higher than a specific value, which depends on the treated substratum. With these dispersions however it is not possible to obtain a textile satisfactory softness.
On the contrary by using an aqueous dispersion according to the present invention, containing a mixture of fluoroacrylates and polyurethanes in the ratios according to the present invention, the textile softness remains unchanged in comparison with the untreated sample and the hydro- and oil-repellent properties are maintained or improved.
It has been found that the dispersions of the invention always show high hydro- oil-repellence values also when the amount of the fluoroacrylic component A) is such that if it was used alone, in the absence of the component B), would give very low hydro- oil-repellence values. This is surprising since the fluoroacrylic polymer concentration in the mixture is lower than that which allows to obtain the same hydro- oil-repellence degree.
It is still more surprising that the hydra-oil-repellence values of the compositions of the invention remain at high values even using the component B) poyurethane which as such has lower hydro- oil-repellence values than the component A).
Therefore the mixture of the two polymers has a synergic effect both as regards the textile hydro- oil-repellence treatment and the softness.
Furthermore it has been unexpectedly found that the hydro- and oil-repellence and softness properties using the dispersion of the invention are maintained even after various textile washings. Tests carried out by the Applicant have shown that after 4 washings in water the treated textiles show substantially unchanged properties. Also washings of textiles treated with detergents do not show meaningful changes with the number of washings.